Critically discuss the view that eating disorders are caused by genetic and biological factors. With reference to the biological and genetic explanations whilst also trying to offer alternative explanations.

Bulimia Nervosa is a more common problem than anorexia and probably more related to dieting. A brief out line is below.

• It is characterised by periods of compulsive bingeing followed by forced vomiting or sometimes the use of laxatives
• Binge eating is reasonably common among dieters i.e. some dieters eat a lot and then make them selves sick. How ever when it occurs more than two times a week over a period of three months it is abnormal.
• Bulimics are also obsessed about their weight although it is usually nearer normal than anorexics. Most of them are within 10% of their correct body weight.

But with every type of disease or condition there are always different schools of thought, which try to prove why the condition has occurred. Explanations for these two conditions can be proven via biological explanations. One type of biological explanation for anorexia is that there are biochemical abnormalities, i.e. the person may have disordered hormones. Secondly it may be because of damage to their neuroanatomy particularly damage to the hypothalamus which may result in loss of appetite, as well as disturbances to menstruation. But lastly and perhaps most importantly Genetic transmission which have had the most studies done on it. Holland et al (1988), found some evidence to form an opinion that anorexia is genetic. His aim was to find whether more MZ twins developed anorexia (twins which came form the same egg therefore 100% genetically similar), or DZ twins (twins which came from different eggs therefore were only 50% genetically similar). He found that far more MZ twins (56%) were concordant to anorexia whereas with DZ twins it was found to be much less (7%). These findings suggest that anorexia have a strong genetic basis because it occurred more when individuals shared the same genes rather than when they were just simply related. How ever, the concordance was not 100%, which suggests that genes simply predispose individuals to develop and eating disorder. Therefore only in certain circumstances does anorexia develop. But some critisim of this could be that as the twins were reared together they also shared the same environmental influences and this may be greater for MZ twins  who look and behave more similarly than DZ twins, and therefore are treated more then same. But also it could be that one twins imitates the twin who developed the disorder first. Therefore showing that it was not genetic at all but more psychological.

There are also biological explanations for Bulimia. These are mostly the same as anorexia. Firstly there are the biochemical abnormalities; decreased serotonin activity may be responsible for bulimia. People with bulimia suffer specifically from carbohydrate craving (Turner et al. 1991) and increased consumption of carbohydrates increases production of serotonin. This has led to the use of SSRIs (selective serotonin reuptake inhibitors) in the treatment of bulimia. But again there is the theory of genetic transmission and a study with twins by Kendler et al. (1991) tried to prove this. It found that there was a 26% concordance rate for MZ twins and a 16% for DZ twins. This suggests that bulimia has a strong genetic component, but it is not as strong as that found in anorexia. About half of the variation in bulimia is due to genetic factors and half to environmental. But with all studies there are criticisms, twins may not be representative. Klump et al. (1999) studied individuals with eating disorders who were MZ, DZ or non-twins and found differences in the groups in terms of the symptoms. This suggests that twins may not be representative of the general population for eating disordered behaviour.